1. Field of the Invention
The present invention relates in general to drainage catheters and, more particularly, to a drainage catheter for draining fluid from a body cavity of a patient.
2. Background Art
Drainage catheters for draining fluid from a body cavity of a patient have been known in the art for many years. Indeed, the practice of inserting a drainage catheter into a body cavity has become a routine medical procedure. Generally, the catheter is inserted into the patient""s body cavity with the aid of insertion tools, such as a needle or stiffening cannula. Once in position, the shape of the flexible tip at the end of the cavity is typically altered to maintain the tip within the cavity, and, in turn, to preclude inadvertent removal of the drainage catheter from the patient""s body. Various ones of these locking catheters have been developed with the capacity to form J-shape, pigtail or other loops at their distal end. The loop is typically formed by retracting a flexible tensioning member, which extends from a distal end down the length of the catheter to a proximal end, where the tensioning member typically exits the catheter. The tensioning member is typically locked into place and sealed at the exit point by a retention member.
For instance, Goldenberg, et al., U.S. Pat. No. 5,352,198 discloses a locking catheter system wherein a tensioning member, in the form of a flexible suture, is capable of forming a loop in the distal end of the catheter. The suture extends through the catheter to the proximal end thereof, where it exits the catheter through a suture exit point. An annular latex sleeve covers the outer surface of the catheter near its proximal end to, in turn, cover the suture exit, thus helping to seal the catheter from leakage. Additionally, an annular silicone sleeve is then rolled over the latex sleeve to both secure the suture in a locked position, and to further minimize leakage.
Somewhat similarly, Paul, Jr., U.S. Pat. No. 5,399,165, discloses a lockable connector positioned near the proximal end of a drainage catheter to lock a tensioning string in place. The lockable connector includes a resilient sleeve having a channel for housing the string and a string exit port. The connector further includes a pivotably attached lever with a cam surface at its sealing end positioned adjacent the sleeve. Pivoting the lever compresses the sleeve, thus locking the tensioning string and the flexible tip in a desired loop orientation. Further, the lever functions to seal the string exit point in the catheter from leakage.
Likewise, Plishka, et al., U.S. Pat. No. 5,989,241, incorporated herein by reference, discloses a drainage catheter apparatus having a hub member through which a tensioning drawstring exits the catheter. The hub includes a sealing member constructed of elastomeric material to seal the drawstring opening and to automatically seal the passage of fluid therethrough, while also enabling extension of the flexible drawing member to lock the distal end of the catheter in a looped configuration.
While these and other devices have worked well for securing the tensioning member and thus the flexible tip in a specific looped orientation, fluid may leak from certain ones of these catheters at the point through which the flexible tensioning member exits the catheter. Moreover, many of these references require a separate member or assembly associated with the tensioning member exit point to seal the exit point from liquid leakage. These separate sealing assemblies are not only additional system components, but also mandate increased manufacturing and assembly time to form a catheter device.
Still other prior art locking catheters require threading of a string or flexible tensioning member through multiple openings in the distal end of the catheter, to form a loop which is suitable for coiling the distal end of the catheter. Typically, a portion of the string is threaded outside the distal end of the catheter to facilitate curling of the flexible tip by mere tensioning of the string. However, a looped threading pattern often requires considerable time and effort in the manufacturing process. In particular, the string must be extended from the proximal end, all the way through the catheter body, out the flexible tip, outside a portion of the distal end, back through the distal end, and back to the proximal end of the catheter. Moreover, if a full 360xc2x0 loop is not required, such as in those situations where only a slight curl or a J-shaped curl is sufficient, a portion of the flexible tensioning member still remains outside of the catheter body. Exposed, the string is subject to severing.
Certain references, such as Pieri, et al., U.S. Pat. No. 2,574,840, and Wallace, U.S. Pat. No. 2,649,092, have sought to anchor the flexible tensioning member within the distal end of the catheter. For instance, the Pieri catheter includes a metal ring positioned in the distal end thereof for securing a tensioning string therein. The string may be pulled through an exit point in the proximal end of the catheter, thus either guiding or curling the tip of the catheter. Somewhat similarly, Wallace anchors a flexible member in the tip of a Malecot catheter. In particular, the flexible member is anchored in the tip of the catheter with a plug, which is permanently affixed therein. Upon tensioning of the string, the distal end of the catheter is pulled toward the proximal end of the catheter, thus extending winged ribs to form drainage openings for drainage of fluids from a body cavity.
While these catheters with an anchored tensioning member appear to be effective for certain applications, the tensioning member is permanently locked within the catheter. Thus, the tensioning member cannot be removed from the catheter, as is common practice before removing a catheter from a patient""s body. It is desirable to remove the string to avoid severing of the string inside the patient""s body or inadvertently retaining a portion or all of the string inside a patient""s body.
Still other references have disclosed anchoring or securing a tensioning member or wire in the tip of a catheter to facilitate steering of the catheter through a patient""s body, including Truckai, U.S. Pat. No. 5,397,304, That, et al, U.S. Pat. No. 5,391,146, Savage, U.S. Pat. No. 5,368,564, Stevens-Wright, U.S. Pat. No. 5,383,852 and Brennen, et al., U.S. Pat. No. 5,439,006. These references generally disclose steering catheters with a closed end for probing desired parts of a patient""s body. Many of these catheters contain electrodes in a closed distal end to take readings or vital signs from the heart region of a patient""s body.
While these catheters work well in a particular context, these catheters are not designed to drain body fluid from a patient. Specifically, the flow of body fluid through an electrode containing flexible tip may damage the ability of the catheter to perform its intended function. Additionally, the steering wire is often permanently anchored in the flexible tip at multiple points, and thus not intended to be removed from those catheters.
Thus, it is desired to provide a drainage catheter which contains a tensioning member exit point which is liquid tight both during curling of the flexible tip and after curling of the flexible tip. Furthermore, it is desired to provide a liquid-tight seal without additional sleeves, assemblies or other catheter components.
It is further desired to provide a drainage catheter wherein the tensioning member is retained directly in the tip of the drainage catheter to facilitate manufacturing of the drainage catheter, while still permitting complete removal of the tensioning member from the drainage catheter before removing the catheter from a patient""s body.
It is also desired to provide a drainage catheter which is relatively easier and less expensive to manufacture, while solving the other needs in the art described above. Particularly, it is desired to provide a method of manufacture of drainage catheter wherein the filament member is molded into the flexible tip. It is also desired to provide a method of manufacturing a drainage catheter to reduce the amount of time and effort in threading a tensioning member within a locking drainage catheter to allow substantial looping of the flexible tip.
These and other objects of the present invention will become apparent in light of the present specification, claims and drawings.
The present invention is directed to a drainage catheter comprising an elongated hollow drainage tube having a proximal end, a distal end, a tip and a flexible region adjacent the tip, a filament routing channel, a hub associated with the proximal end of the elongated hollow drainage tube, and a filament member associated with the distal end for altering the shape of the flexible region to facilitate retention of the drainage tube in a patient""s body. The filament member is preferably slidably positioned within the filament routing channel in the distal end of the drainage tube to permit removal of the filament member from the catheter.
In one embodiment, the drainage catheter further includes an insert member which is formed into the distal end of the elongated hollow drainage tube to form the filament routing channel. In one embodiment, the insert member is preferably constructed from a plastic of a higher durometer than that forming the elongated hollow drainage tube, yet which is still chemically bonded and/or fused to the inside of the drainage tube. In another embodiment, the insert member is formed of the same material as the drainage tube, thus melt-flowing into the outer drainage tube. In yet another embodiment, the insert member is formed from a material distinct from the drainage tube, such as stainless steel.
In another embodiment, the drainage catheter is formed with a second insert member to alter the orientation of the filament member in the distal end of the elongated hollow drainage tube.
In yet another embodiment, the filament member remains inside the elongated hollow drainage tube until exiting through the hub. In a contrasting embodiment, the filament member extends outside at least a portion of the drainage tube to facilitate alteration of the shape of the distal end of the drainage tube.
The filament member preferably exits the catheter through the hub, which further includes at least one filament member passageway. The at least one filament member passageway enables slidable movement of the filament member therein, while also maintaining a liquid tight seal substantially precluding leakage through the hub.
The present invention also addresses a method for manufacturing the drainage catheter including the steps of positioning the filament member inside the distal end of the elongated hollow drainage tube, energizing the distal end of the elongated hollow drainage tube to form a filament routing channel positioned within the distal end such that the filament member is positioned within and slidably routed through said filament routing channel, running the filament member through at least a portion of said elongated hollow drainage tube such that the filament member emanates from the proximal end of the drainage tube, and forming a hub on the proximal end of said elongated hollow drainage tube.
In one embodiment, the method further includes the step of associating the filament member with the insert member occurs before the step of positioning the filament member inside said distal end of the elongated hollow drainage tube. To this end, the step of positioning the filament member inside the distal end of the elongated hollow drainage tube further includes orienting the insert member and the filament member inside the distal end of the elongated hollow drainage tube.
In another embodiment, the step of orienting the insert member and the filament member inside the distal end of the elongated hollow drainage tube provides the filament member with an orientation relative to the inside surface of the elongated hollow drainage tube, and wherein the method further includes the step of positioning the filament member relative to a second insert member inside the distal end of the elongated hollow drainage tube to alter the orientation of the filament member relative to the inside surface of the elongated hollow drainage tube.
In yet another embodiment, the step of positioning the insert member and filament member inside the distal end of the elongated hollow drainage tube further includes the steps of positioning the insert member on a smaller diameter portion of a mandrel which includes a smaller diameter portion and a larger diameter portion, placing the elongated hollow drainage tube over the insert member and the filament member such that the insert member is inside the distal end of the elongated hollow drainage tube and such that the filament member runs inside the elongated hollow drainage tube.
In yet another embodiment, the method for forming a drainage catheter further includes the step of forming the distal end of the elongated hollow drainage tube to a desired shape, and which step preferably further includes inserting the distal end of the elongated hollow drainage tube into a die.
In another embodiment, the step of forming a hub onto the proximal end of the elongated hollow drainage tube includes forming the hub directly around the filament member, thereby creating at least one filament member passageway extending through the hub to house the filament member, and to permit slidable movement of the filament member through the hub. Preferably, the formation of the hub around the filament member renders the hub substantially liquid tight to prevent leakage of fluids from the drainage passageway of the hub through the filament member passageways.